DE1281433B - Process for the production of vinyl acetate - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENTAMi

EDITORIAL

Int. Cl .:

C07c

BOIj

German class: 12 ο -19/03
12 g-11/00

Number: 1281433

File number: P 12 81 433.4-42 (A 52654)

Filing date: June 3, 1966

Opening day: October 31, 1968

■ H »
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A mixture of ethylene, acetic acid and oxygen is already used to produce vinyl acetate subjected to a vapor phase reaction in the presence of a catalyst serving as the main catalyst component at least one of the following metals: platinum, palladium, rhodium, ruthenium and iridium, as well as at least one of the following metals as a promoter: copper, silver, zinc, cadmium, tin, lead, chromium, Contains molybdenum, tungsten, iron, cobalt and nickel.

A disadvantage of this process is that the activity of the catalyst decreases with prolonged reaction time. Although this procedure is large-scale can carry out, so there are difficulties with the regeneration of the Connected catalyst or the supply of fresh catalyst. In addition, during regeneration Catalyst losses have to be accepted.

In the production of carboxylic acid esters by reacting ethylene, oxygen and carboxylic acids in the presence of a palladium, rhodium or platinum salt, which is a copper, zinc, mercury, lead, Chromium, manganese, iron or nickel salt has been added, it is known to cause the reaction in the presence of a To make hydrogen halide. However, this was always carried out in the liquid phase. A continuous one The course of the reaction was practically impossible. Ultimately, there is the selectivity of vinyl acetate formation greatly reduced because large amounts of acetaldehyde are formed as a result of side reactions.

When studying the mechanism responsible for reducing catalyst activity It has been shown that the active sites on the surface of the catalyst are not caused by catalyst poisons be destroyed in the reactants, such as ethylene, acetic acid and oxygen, or in the resulting product are contained, but that rather the sintering of the main catalyst component this is the cause of this during the reaction. The sintering of the main catalyst component can is known to be prevented by a small amount of chloride ions in the catalyst mass, however the chloride ions react with ethylene to form ethylene chloride, mainly ethylene dichloride.

The process for the production of vinyl acetate by reacting ethylene and acetic acid and Oxygen in the gas phase in the presence of a catalyst, which is one of the metals platinum, palladium, Rhodium, ruthenium, iridium, their chlorides, oxides, hydroxides and / or salts that are "in situ" Process for the production of vinyl acetate

Applicant:

Asahi Kasei Kogyo Kabushiki Kaisha, Osaka (Japan)

Representative:
Dr. O. Dittmann, KL Schiff

and Dr. A. v. Füner, patent attorneys,
8000 Munich 90, Bereiteranger 15

¹ S Named as inventor:
Naoya Kominami,
Kusuo Kawarazaki, Tokyo

_ao claimed priority:

Japan June 4, 1965 (32 668)

form the corresponding chlorides, and as a promoter one of the metals copper, silver, zinc, cadmium, tin, lead, chromium, molybdenum, tungsten, iron, cobalt, nickel, their chlorides, oxides, hydroxides and / or salts thereof, which » in situ "form the corresponding chlorides, is characterized according to the invention in that the reaction is carried out in the presence of 0.1 to 50 mg of hydrogen chloride per 100 liters of gas mixture.
According to the process of the present invention, the decrease in catalyst activity can be completely prevented and the catalyst life can be made practically indefinitely. Vinyl acetate can thus be produced economically on an industrial scale without the need for special equipment and measures for regenerating the catalyst. A better yield per unit weight of catalyst used is also achieved.
In the process according to the invention, the amount of hydrogen chloride can vary in the range given above, depending on the catalyst mass, reaction temperature, composition of the gaseous reactants and their space velocity. When the amount of hydrogen chloride exceeds the upper limit, the concentration of chloride ions in the catalyst increases, and large amounts of acetaldehyde and carbon dioxide are formed

809 629/1463

3 4

By-products, so that the yield of vinyl acetate per 100 g of activated carbon as a carrier. In that at 16O ⁰ C strongly decreases and sometimes the value of practically kept reaction vessel was reached with a space zero. On the other hand, the amount is less velocity of 96 hour time ^1, a gas mixture of, as indicated above, the concentration of the ethylene, oxygen, acetic acid and hydrochloric chloride ions is reduced so much that a decrease 5 in a molar ratio of 60: 40: 20 : 0.020 initiated, the catalyst activity takes place. . The analysis of the outflowing gas was based on

A gas chromatographic route is carried out for the process according to the invention. She showed, Reaction temperature between 80 and 180 ° C, so that at the start of the reaction only acetaldehyde and carbon pulls out. Below. 80 ° C the catalyst dioxide was formed that the formation of the vinyl activity and the yield of vinyl acetate is too low. io acetates started after 5 hours and production If you work above 180 ° C, the vinyl acetate increases evenly after 10 hours. Formation of ethylene dichlorides too much prevalent, during the state of equilibrium the and the activity of the catalyst for the formation of amounts of vinyl acetate and acetaldehyde 1.6% and Vinyl acetate is almost lost. 5.5% ■ The reaction products contained a trace

The redox catalyst system can use ethylene chloride without a carrier. The reaction became continuous be used. Carried out for 6 days for the inventive method without any decrease but also catalysts on carriers can drive the catalyst activity made noticeable, can be used, including porous materials, such as. For comparison, Example 1 was under identical

Activated carbon, silica gel, activated alumina, conditions repeated with the exception that that Kieselguhr or pumice stone. Activated charcoal is ao gas mixture did not contain hydrogen chloride. At the preferred. Yields of vinyl

Obtained in the preparation of the catalyst for the acetate and acetaldehyde of 1.6% and 5.5 ° / _0, a method of the invention is indeed dipping substantially the same as those preferred in the previous method, but other setting may attempt. However, the usual catalyst methods began to be used. 35 activity decrease after just 72 hours. she

The proportion of the promoter to the main catalyst was reduced to about 40% of the equilibrium state in the component in the catalyst system is reduced over the course of 95 hours. The catalyst 1: 1 in atomic ratio and preferably greater than 5: 1. activity deteriorated further to less than

When performing the 5% according to the invention at the equilibrium state after 7 days. Procedure is not 30 R "· 19 for initiation of the reaction

necessarily some particular molar ratio example

from oxygen to ethylene required. However, a palladium chloride-copper XIty-chloride catalyst with an increasing molar ratio of oxygen to carbon on activated carbon, together with packing elements of ethylene, also increased the amount of oxidation products, introduced into the same reaction vessel, that is, of carbon dioxide, carbon monoxide and water, 35 Example 1 was' used, and so that the yield decreases to vinyl acetate to form. When a catalyst containing free metal in an otherwise decreasing the molar ratio of oxygen to hydrogen stream at a temperature of 400 ⁰ C ethylene, the reaction rate is reduced. the introduced into the reaction vessel This is why a molar ratio of catalyst consisting of 4.8 g of palladium chloride and oxygen to ethylene of 1: 1 to 50: 1 is preferred. 40 10.9 g of copper (II) chloride per 100 g of activated carbon as

Each area is in the carrier in the same way. In the reaction vessel kept at 165 ° C ratio of ethylene to acetic acid was possible, but with a space velocity of 150 hours - ¹ a molar ratio of ethylene to acetic acid was a mixture of ethylene, oxygen, acetic acid and 1:10 to 10: 1 , in particular from 3: 1 to 3: 4, before hydrogen chloride is added in a molar ratio of 40: 40: 20: 0.037. 45 introduced. Vinyl acetate and acetaldehyde started

The preferred space velocity for the gases to form after 15 minutes. The formation of a mixture consisting of ethylene, acetic acid, chlorine-vinyl acetate became uniform after 2 hours. ' hydrogen and oxygen, is 50 to 1000 hours - ¹ In the equilibrium state, the yield was about 100 to about 300 hours - ¹ in particular. Vinyl acetate and acetaldehyde 3.6% and 10.1%, respectively. It

The reaction pressure can be either atmospheric, so even 7 days after the start of the reaction, none pressure or overpressure, provided that the significant decrease in catalyst activity observed reactants be observed under the reaction conditions that the gas phase is present. Example 3

Any type of bed, rigid, moving, or whirling, can be used to carry out the invention according to the method are used. on activated aluminum oxide, manufactured according to.

The yields of vinyl acetate and acetaldehyde in an immersion process were compared to the methods described in Example 1 the following examples are given in the reactor described in terms of throughput yields. The catalyst

indicated, based on the ethylene supplied. consisted of 15 g of platinum hydrochloric acid and 21 g

_R. 60 iron (III) chloride per 100 g activated aluminum oxide.

^{e l s} P ^{l e} A gas mixture of ethylene, air, acetic acid and

A palladium chloride-copper Cl ^ chloride catalyst hydrogen chloride in a molar ratio of 30: 50: 20: 0.031 tor on granulated activated carbon, prepared by a was in the reaction vessel at a space speed immersion process, was together with packing speed of 300 hours ^-1 and a temperature of 65-100 ° C in a reaction vessel made of hard glass with an interior. In the state of equilibrium, diameters of 30 mm were given, which could be heated in a nitrate yield of vinyl acetate and acetaldehyde of 1.3% bath. The catalyst passed or 4.3% was retained. The reaction products contained a small amount of carbon dioxide and a trace from 2 g of palladium chloride and 10 g of copper (II) chloride

Ethylene chloride. There was no appreciable decrease in the catalyst activity even after 7 days observed.

Example 4

A ruthenium nitrate, silver nitrate-silica gel catalyst was placed in the reaction vessel of Example 1 and heated in a nitrogen stream at 45O ⁰ C for 2 hours. The catalyst consisted of 2 g of ruthenium nitrate and 11.3 g of silver nitrate per 100 g of silica gel as a carrier. In the reaction vessel, which was maintained at 150 ⁰ C, at a space velocity of 115 Def ^1, a gas mixture of ethylene, air, acetic acid and hydrogen chloride in a molar ratio of 25: 50: 25: 0.044 initiated. At equilibrium, the yields of vinyl acetate and acetaldehyde 6.3% and 21.1 ° / _0th A noticeable decrease in the catalyst activity was not observed even after 7 days.

ao

Example 5

An iridium chloride-cadmium acetate catalyst on activated carbon was added to the reaction vessel. The catalyst consisted of 9.0 g of iridium chloride and 23.2 g of cadmium acetate. 20: 20: In the held at 13O ⁰ C reaction vessel ^"1, a gas mixture of ethylene, oxygen, acetic acid and hydrogen chloride in a molar ratio of 30 was a space velocity of 230 h. 0.025 introduced At the equilibrium condition, the yield of vinyl acetate and acetaldehyde 1. , 3 ° / ₀ and 2.8%, respectively. A significant decrease in the catalyst activity was not observed even after 7 days.

Example 6

35

Example 5 was repeated with the difference that iridium chloride-zinc acetate on activated carbon was used became. The catalyst consisted of 9.0 g of iridium chloride and 21.9 g of zinc acetate. In a state of equilibrium the yields of vinyl acetate and acetaldehyde were 1.1% and 2.5%, respectively. There was a notable decrease in catalyst activity not observed even after 7 days.

Example7

Example 5 was repeated with the difference that platinum hydrogen chloride - lead acetate on activated carbon was used. The catalyst consisted of 0.01 mole of platinum hydrogen chloride and 0.07 mole of lead acetate 100 ml of activated charcoal as a carrier. At the equilibrium state, the yields of vinyl acetate were and acetaldehyde 1.0% and 2.5%, respectively. There was a notable decrease in catalyst activity not observed even after 7 days.

Example 8

A catalyst consisting of 4.2 g of rhodium chloride and 11.1 g of chromium chloride on 100 g of activated carbon was placed together with packing in a glass reaction vessel with an internal diameter of 30 mm. The reaction vessel was at a space velocity of 120 Def ^1, a gas mixture of ethylene, oxygen, acetic acid and hydrogen chloride in a molar ratio of 50: 0.35 fed: 25: 25th In the equilibrium state, the yields of vinyl acetate and acetaldehyde were 2.8% and 5.1%, respectively. A significant decrease in the catalyst activity was not observed even after 7 days.

Example 9

3.7 g of platinum hydrogen chloride and 12 g of ammonium molybdate were applied to 30 ml of activated carbon by an immersion method. The resulting mixture was heated in air for 4 hours at 500 ^° C. and then placed in a reaction vessel. The reaction vessel kept at 170 ⁰ C was treated with a space velocity of 280 hr ^"1, with a gas mixture of ethylene, air, acetic acid and hydrogen chloride in a molar ratio of 20: charged 0.071 In equilibrium, the yield of vinyl acetate and acetaldehyde. 4: 60: 20. , 8% and 6.1%, ^{respectively, no} significant decrease in the catalyst activity was observed even after 7 days.

The experiment was repeated under the same conditions with the difference that 16 g of ammonium tungstate were used. In the equilibrium state, the yields of vinyl acetate were and Acetaldehyde 3.4% and 4.6%, respectively. A noticeable decrease in catalyst activity was also observed after Days not observed.

Claims (5)

Patent claims: 1. Process for the production of vinyl acetate by reacting ethylene with acetic acid and Oxygen in the gas phase in the presence of a catalyst, which is one of the metals platinum, palladium, Rhodium, ruthenium, iridium, their chlorides, oxides, hydroxides and / or salts, the Form the corresponding chlorides "in situ", and as a promoter one of the metals copper, silver, Zinc, cadmium, tin, lead, chromium, molybdenum, tungsten, iron, cobalt, nickel, their chlorides, Oxides, hydroxides and / or salts thereof, which "in situ" form the corresponding chlorides, contains, characterized in that the reaction is carried out in the presence of 0.1 to 50 mg hydrogen chloride is carried out per 100 liters of gas mixture. 2. The method according to claim 1, characterized in that the reaction with a carries out oxygen-containing gas. 3. The method according to claim 1 and 2, characterized in that the reaction at a Molar ratio of ethylene to acetic acid of 3: 1 to 3: 4. 4. The method according to claim 1 to 3, characterized in that the gaseous mixture of the reactants is introduced into the reaction chamber at a space velocity of 50 to 1000 hrs- ¹ and preferably 100 to 300 hrs- ¹ . 5. The method according to claim 1 to 4, characterized in that the reaction is carried out in Carries out the presence of a catalyst which is applied to a carrier. Considered publications:
German Auslegeschriften No. 1179 928, 1179 088. 809 629/1463 10.68 © Bundesdmckerei Berlin